I am normally a trainstrainstrains guy, but I have a space project that i have been neglecting over the past 5 years and thought that this would be a good opportunity to renew my interest in the project. And I miss the old spaceheads.

I have formerly been known as Mr 8 wide and have an appetite for delicious Spamcake:-d

Suction is a fictitious force. As you correctly pointed out, an airplane wing creates lower pressure on top and high pressure on the bottom. However, the wing doesn't rise because the air on top pulls; Both the air on top and the air on the bottom push on the wing. The higher pressure below the wing means that the air below the wing pushes harder, creating a net upward force (aka lift).

Blake wrote:Suction is a fictitious force. As you correctly pointed out, an airplane wing creates lower pressure on top and high pressure on the bottom. However, the wing doesn't rise because the air on top pulls; Both the air on top and the air on the bottom push on the wing. The higher pressure below the wing means that the air below the wing pushes harder, creating a net upward force (aka lift).

Okay, "sucks" isn't quite the word for what I'm talking about. That was just a little trains pun

But back to our discussion-- doesn't the void actually initiate the push of air? It seems to me that the air is responding to the unequal pressure and the void is the reason for the movement. And since the void of space is the default setting for the universe, it is the cause.

Suppose you have a sealed container full of air. Air molecules are constantly slamming into the walls of the container. Each collision exerts a little bit of force. Integrating the force of all those collisions over a small area gives you the pressure. If you remove the lid in a vacuum, there will be nothing to deflect the air molecules back into the interior of the container, so they escape. As air molecules escape, they create an area of lower pressure near the lid, and the effect propagates. The net outward airflow is a result of pushing from the inside of the container, though, not pulling from the outside.

It's just word play really, though... if, by the word "suction", you mean air presure pushing, then there is such a thing as suction. But if, as the article explains, you mean that the void "attracts" the air, then I guess there is not.

Blake wrote:Suppose you have a sealed container full of air. Air molecules are constantly slamming into the walls of the container. Each collision exerts a little bit of force. Integrating the force of all those collisions over a small area gives you the pressure. If you remove the lid in a vacuum, there will be nothing to deflect the air molecules back into the interior of the container, so they escape. As air molecules escape, they create an area of lower pressure near the lid, and the effect propagates. The net outward airflow is a result of pushing from the inside of the container, though, not pulling from the outside.

I appreciate you taking the time to give me these physics tutorials, Blake Given your example, I see now how the void isn't responsible for the flow of air, just a place (SPACE!) for it to go.

BTW I took a few moments to check out your web site. Very nice; you are a multi-talented guy! One would suppose that a Renaissance Man like yourself would be hanging out in http://www.classic-castle.com

Hyperlinked text: roll your mouse over the "URL" button in the full editor, and it will show you! Here's a tutorial:If you type:[url.]www.jiggywiggy.com[/url.]It will appear as: www.jiggywiggy.com (as a link)Which you already know. If you typed[url.=www.jiggywiggy.com]some site that I made up[/url.]It would appear as:"some site that I made up" and it will link to jiggywiggy.com when you click the text.

Hopefully I didn't confuse the sitatution more :-). Enjoy!

PS. you gotta take the periods out that i added after "url"... those are just so the page won't read the script as an actual link in my example

It's just word play really, though... if, by the word "suction", you mean air presure pushing, then there is such a thing as suction. But if, as the article explains, you mean that the void "attracts" the air, then I guess there is not.

Thanks for the linkie, BlackiceP8ntball-- it was very informative, as was your hyperlinked text which showed me how I can do it for myself! SPACE doesn't do this afterall!